Upon sale or transfer of ownership of any dwelling used for human occupancy, the dwelling unit shall have installed and operating a products of combustion detector, other than heat, conforming to the National Fire Protection Association Standards 74 as amended. The detectors shall be mounted on the ceiling or wall within one (1) foot of the ceiling, centrally located in the corridor or area giving access to rooms used for sleeping purposes. Where sleeping rooms are on the upper level, the detector shall be placed at the center of the ceiling directly above the stairway. Each detector must have the approval of the California State Fire Marshal and shall be tested during the inspection. (Ord. 727 § 1, 1985)